The effect of periodic strain on the beat wavelength between the guided LP01 and the leaky LP11 modes is approximated around the LP11 mode cutoff. An abrupt change of the beat wavelength as a function of optical wavelength signifies the onset of the cutoff region. An order parameter is suggested to characterize the transition of the LP11 mode from a guided to a cladding mode.
© 1988 Optical Society of America
H. Grebel and M. Mezhoudi, "Effect of periodic strain on the leaky modes in single-mode fiber," Appl. Opt. 27, 4819-4821 (1988)